execute stored procedure based on condition - sql

Question

i tried to insert data in database using stored procedure but according to some condition. for example if data is already exists in database the the stored procedure should not be executed.
i am doing the following code but it return 0 every time rather then i want. What can i do
ALTER PROCEDURE dbo.SaveUser
(
#cid int,
#firstname varchar(20),
#lastname varchar(20),
#dob datetime,
#gender varchar(20),
#add varchar(100),
#email varchar(40),
#quali varchar(20),
#yop varchar(15),
#exp varchar(10),
#pass varchar(20)
)
AS
declare #result int
if EXISTS( select Email_ID from Registration where Email_ID=#email )
begin
set #result=4;
return #result;
end
else
begin
insert into Registration values(#cid, #firstname, #lastname, #dob, #gender, #add, #email, #quali, #yop, #exp, #pass );
set #result =0;
return #result;
end

Answer 1

You can simply proceed as follows;
ALTER PROCEDURE dbo.SaveUser
(
#cid int,
#firstname varchar(20),
#lastname varchar(20),
#dob datetime,
#gender varchar(20),
#add varchar(100),
#email varchar(40),
#quali varchar(20),
#yop varchar(15),
#exp varchar(10),
#pass varchar(20)
)
AS
BEGIN
DECLARE #return int
if NOT EXISTS(select Email_ID from Registration where Email_ID=#email)
insert into Registration values(#cid, #firstname, #lastname,
#dob, #gender, #add, #email,
#quali, #yop, #exp, #pass )
If (##ERROR <> 0)
Begin
Set #return = 4
Else
Set #return = 0
End
Return #return
END

Answer 2

You can use raiseerror event for this scenario
if EXISTS( select Email_ID from Registration where Email_ID=#email )
begin
RAISERROR(N'Email id already exist.', 10, 2,'')
end
Here 10 is severity level and according to severity level sql server identified as info meassage or exception. For more information
RaiseError
Database Engine Severity Levels

Answer 3

Try this one -
ALTER PROCEDURE dbo.SaveUser
(
#cid INT,
#firstname VARCHAR(20),
#lastname VARCHAR(20),
#dob DATETIME,
#gender VARCHAR(20),
#add VARCHAR(100),
#email VARCHAR(40),
#quali VARCHAR(20),
#yop VARCHAR(15),
#exp VARCHAR(10),
#pass VARCHAR(20)
)
AS BEGIN
IF NOT EXISTS(
SELECT 1
FROM dbo.Registration
WHERE Email_ID = #email
) BEGIN
INSERT INTO dbo.Registration
SELECT #cid, #firstname, #lastname, #dob, #gender, #add, #email, #quali, #yop, #exp, #pass
RETURN 0;
END
RETURN 4;
END